Not applicable.
The present invention relates to a restraint harness for use on-a tow bar apparatus having tension release mechanism, and more particularly, relates to a tow bar restraint harness for use in maintaining the integrity of an aircraft tow bar apparatus having a shear pin tension release mechanism after pin shear has occurred
A number of tow bar apparatuses incorporate into their design the use of a tension release mechanism. Such tension release mechanisms serve to relieve the tension being placed on the tow bar apparatus by the load under tow when the tension exceeds a predetermined threshold. This threshold is typically set to provide for the release of any tension being exerted on the tow bar apparatus by the load under tow before the tension reaches a level at which it may cause damage to the tow bar apparatus, the tow vehicle, and/or the load under tow. For example, in the case of a typical vehicle tow bar apparatus, the tension release mechanism is calibrated to provide for the release of tension before any damage can occur to the vehicle under tow.
The tension release mechanism of a vehicle tow bar apparatus typically includes a shear pin tension release mechanism. In a shear pin tension release mechanism of a vehicle tow bar, a shear pin is typically used to join two sections of the tow bar apparatus. The shear pin is positioned such that the tension exerted on either of the two sections of the tow bar apparatus connected by the shear pin is born by the shear pin. If the tension forces exerted on either of the two sections of the tow bar apparatus exceeds the shear strength of the shear pin, the tension forces will act to shear the shear pin. When pin shear occurs, the two sections of the tow bar apparatus formerly connected by the shear pin will be disconnected. Accordingly, by providing a shear pin that is designed to shear before the tension forces on the tow bar apparatus reach a level at which damage to the tow bar apparatus, tow vehicle, and/or vehicle under tow would occur, the use of a shear pin tension release mechanism serves the valuable purpose of releasing the attached portions of the tow bar before any damage can occur.
While the shearing of the shear pin serves to release the tension on the tow bar apparatus, it also serves to disconnect the vehicle under tow from the tow vehicle. If the vehicle under tow is manned by an operator when pin shear occurs, the operator may bring the vehicle to a stop. However, a difficulty may arise when the vehicle under tow is unmanned. In such case, when pin shear occurs, the vehicle formerly under tow is placed into a free rolling condition without a means to bring it to a safe stop. Absent any remotely controlled braking or guidance systems on board the vehicle formerly under tow, the vehicle must generally be allowed to roll out of control until natural forces bring it to a stop. It will be appreciated that such natural forces may often include obstacles or individuals that lie in the path of the vehicle.
While many vehicles include the capacity to be manned by an operator during towing operations, many other vehicles do not. One such vehicle is an unmanned or drone aircraft, also known as an unmanned aerial vehicle or UAV. In the course of operating a UAV, it is often necessary to tow the UAV from one location to another. Such towing is traditionally accomplished through the use of an aircraft tow bar apparatus having a shear pin tension release mechanism. Such a tow bar apparatus is typically connected to the nose landing gear of the UAV. The shear pin tension release mechanism on the tow bar is thus designed to release the section of the tow bar that is attached to the UAV upon encountering unacceptable tension forces in the tow bar apparatus. For example, before the tension forces on the aircraft tow bar apparatus reach a level at which the nose landing gear of the UAV would be damaged, the shear pin is designed to shear. When pin shear occurs, the UAV is placed in a free rolling condition with the forces of nature being the only means available to bring the UAV to a stop. Such a condition is undesirable and can result in damage to the UAV, damage to other property, or, worse yet, injury to personnel in the path of the UAV.
Accordingly, it would be advantageous to provide an apparatus that maintains the integrity of the connection between an aircraft tow bar apparatus having a shear pin tension release mechanism and the nose landing gear of a UAV after pin shear has occurred. Furthermore, it would be advantageous that such an apparatus maintain the integrity of this connection in directions both parallel and lateral to the tension being placed on the tow bar, so that the UAV under tow may be safely and orderly maneuvered to a stop after pin shear has occurred using the tow vehicle. More broadly, there exists a need for an apparatus that maintains the integrity of the connection between any vehicle towing device having a tension release mechanism and the vehicle under tow after the tension release mechanism has been triggered so that the vehicle under tow maybe safely and orderly maneuvered to a stop using the tow vehicle.
In accordance with one form of the present invention, there is provided a restraint harness that includes a longitudinal load strap member. The longitudinal load strap member defines an upper surface, a lower surface, a closed end. A primary anchor is fixedly connected to the upper and lower surfaces adjacent to the open end and a primary lateral restraint is fixedly connected to the upper and lower surfaces adjacent to the closed end. A secondary lateral restraint is fixedly connected to the upper surface between the primary anchor and said primary lateral restraint.
It is a feature of the present invention to maintain the integrity of a tow bar apparatus having a tension release mechanism after the tension release mechanism has been triggered, in directions both parallel and lateral to the tension being placed on the tow bar by the load under tow.
It is another feature of the present invention to maintain a first tow bar portion in attachment with a second tow bar portion that was formerly connected to the first tow bar portion.
It is yet another feature of the present invention to maintain the integrity of an aircraft tow bar apparatus having a shear pin release mechanism after pin shear has occurred, in directions both parallel and lateral to the tension being placed on the tow bar by the aircraft under tow.
Yet another feature of the present invention is to maintain the integrity of an aircraft tow bar apparatus having a shear pin tension release mechanism after pin shear has occurred, to allow control to be maintained over the aircraft under tow until the aircraft can be brought to a stop and the shear pin replaced.
Accordingly, the present invention provides solutions to the shortcomings of prior tow bar apparatuses and arrangements employed to tow a variety of vehicles and apparatuses, including aircraft. Those of ordinary skill in the art will readily appreciate, however, that these and other details, features and advantages will become further apparent as the following detailed description of the preferred embodiments proceeds.